I'm the proud new owner of a Decware Mini Torii. I purchased this amp used here on the classifieds forum and have had it running in my studio for almost a week now.

So far I’ve tried a few 6v6 combinations, including the uber-expensive Eclipse-Pioneer/Bendix 5992, and I’ve spent a few hours with some Sylvania 6y6 tubes. But the combination that really works best for me is the Valve Art 350b driven by 12at7s.

I’ve had a lot of single ended tube amps through my doors in the past 6-7 years, including six 300b amps that ranged from simple little affairs to full blown WE91a amps, and none of them has had the “magic” the way the Mini Torii with the 350b do. The only amp I currently have that is better sounding in any way than the Mini is a very unusual one–off single ended 71a amp. If Steve ever decided to make a 71a, I’d be first in line. Until then, the Mini Torri with the 350bs is the cats meow.

If you haven’t tried the 350B, I’d urge you to spend the $40 and give it a shot. Bottom line, this Mini Torii is a fantastic amplifier.

Hi Kevin! Your story is music for my ears. My M-T should be shipped sometime mid April, and was wondering what tubes to roll once it gets broken-in. There are so many possible combinations (NOS and otherwise), that just picking some of them becomes a difficult task.

I know that current production Tung-Sol 6V6's are great, and that the JJ's are pretty good, yet more similar to 6L6's. There's also the NOS RCA black plate and the Brimar 6V6's with great reviews. I was not aware of the ones you mentioned, so definitely will give them a try.

May I ask what speakers are you using with the M-T? Tubes usually sound better or not so much depending on analog components' synergies. Any particular brand on the 12AT7s?

I saw your site with the rich audio gear collection, congrats! For one thing, I was not familiar with the Decware Signature Monos, which seem very special. Good to know about the great sound of open baffle DIY's on Nirvana drivers.

I was wondering if you have tried either the 12aU7 or 12aX7 driver series in the Mini-Torii. I know these are compatible, and was wondering how much can one reduce the already high gain available with the 12aT7 (1.0 volt for full output), by replacing the 12aT7 with a lower gain driver. Hopefully, these alternatives may not imply sound quality tradeoffs?

Nice to hear, probably the added voltage regulation stage on the M-T makes a significant difference. I have great expectations on that amp!

Thanks for the info on the drivers, I was not aware the 12aX7 was even higher gain. I'm not even sure the high gain will be an issue, but since my sources are always going to be on the (2+) V, I thought it may help to lower the drivers gain somewhat. We'll see.

I just found out:

Mu ranking is 12AU7 (20), 12AV7 (40), 12AT7 (60) and 12AX7 (100)

I suppose the higher the Mu rating, the higher the gain. What would be the sound tradeoffs involved though? Thanks for any tips.

I read somewhere that Steve voiced this amp around the 12at7, so I have stuck with that so far in order to have a level playing field while trying various output tubes. Plus, the 12at7 is often cheaper for good tubes like telefunkens, etc, so that is a big advantage if you want to buy a variety of input tubes to play with.

If you are curious about the gain , best to just try a 12au7 or 12ax7 and see how it sounds. It won't hurt the amp...

Input tubes often have a bigger effect on the sound than output tubes do.

Aside from the gain issues, seems like the logical rolling scenarios would be trying different 12aT7's at a time, combined with compatible output tubes. As you pointed out, 12aT7 variations may probably have major impact on the end sound. This entails a compounded (huge) number of´possible combinations.

How are we supposed to narrow down market-available best possible choices, when only a fraction is practically/feasibly possible to test? Are there any specific rules of thumb?

The problem is further compounded by the effect of other components in the particular setup. Probably most of the possible 12aT7/Output tube combinations will sound great, but I'm just wondering.

The first thing anyone should try on a mini torii is the 12AU7 and the 12AT7 to find out which gain works best in their system. Often it is the 12AU7's. Once you settle on that you can move onto trying different output tubes. And since you have at that point both 12AU7 and 12AT7 it would probably be a good idea to try both with each output tube as you roll.

Hello Steve! Thank you for the tip. Could you please tell us what driver tube comes stock as the Mini Torii is shipped (that way I can order the other one in advance)? Thanks again for your assistance.

I have owned several single ended triode and single ended pentode amps and rolled more tubes than a sane man should. Don't go nutsrolling tubes. There will be one combination that really floats your boat with your associated equipment and when you find it...stick with it. Just MHO.

I am going to call Steve tomorrow and hopefully order a Mini Tori as I think it will be a good match for my speakers.

I'd agree, except how do you go about finding that particular combination?

I would suggest to ask Steve for likely robust, particular brands' driver/output tube combinations, he may feel will be adequate for most settings. For example, a particular brand 12aU7 with a synergistic 6_6 output tube he knows works in most cases. Same with the 12aT7 (you need both due to possible gain adjustment with your own setup).

This insight will bypass the never-ending trial-and-error process involved, or at least limit it significantly.

I'll certainly encourage you to go with the Mini-Torii if your listening context suits its character and specs. It is the ideal in my case, and I'm eagerly waiting for its arrival.

BTW, if you get those combinations from Steve, please don't hesitate in publishing them here!